Unity Drop-In Inventory System

A complete, production-ready inventory system for Unity. Drop it into any project and get a fully functional RPG-style inventory with hotbar in minutes — no boilerplate code required.

What's included:

• Item System: ItemSO ScriptableObject with icon, display name, description, stack settings, buy/sell prices, 3D world prefab, and optional localization support.
• Inventory Grid: Configurable grid of slots split into main inventory and hotbar sections. Each slot supports per-slot filtering by item type and/or item ID.
• Hotbar: 10-slot hotbar with keyboard shortcuts (1–9, 0), mouse wheel navigation, and integration with the active slot system for quick item use.
• Drag & Drop: Full drag-and-drop between slots with intelligent stacking, automatic stack merging when dragging onto the same item type, slot-to-slot swapping, and item splitting via right-click while dragging.
• Quick Move: Shift + Right Click instantly moves items between the main inventory and the hotbar.
• Slot Filtering: Each slot can be configured to accept specific item types (e.g. "Weapon", "Potion") or specific item IDs, using union (OR) logic — perfect for equipment slots, potion pouches, and crafting stations.
• Save & Load: JSON-based persistence in persistentDataPath with automatic saving on every inventory change and automatic loading on start. Fully customizable via autoSaveOnChange and autoLoadOnStart toggles.
• Optional Localization: Compile-time toggle (USE_UNITY_LOCALIZATION define) for Unity Localization package support — item names and descriptions can be localized with fallback to plain strings when localization is not used.
• Visual Styling: InventoryStyleSO controls per-item-type backgrounds, frames, and colors. Each ItemSO can override with specialBack / specialFrame sprites for unique rarity visuals.
• 3D World Pickup: PickUpManager + PlayerPickUpTrigger + UnitOnGround enable 3D world items that can be picked up into the inventory by walking over them.
• Event System: 7 C# events (onItemSpawned, onItemAdded, onItemRemoved, onSlotSelected, onQuickMoved, onInventoryChanged, onActiveSlotChanged) for seamless integration with custom gameplay code.
• Editor Tools: Custom property drawers for item type dropdowns, searchable dropdown windows for filter configuration, and a menu command to generate a default InventoryStyleSO asset.
• Architecture: Clean separation of business logic (InventoryModel — pure C# with no UI coupling) and presentation (InventoryUIController, InventorySlot, InventoryItem). Assembly Definition Files keep editor and runtime code properly isolated. DontDestroyOnLoad support via InventorySystemRoot.

Game genres supported:

• RPG — inventory, consumables, equipment, quest items
• Survival / Crafting — resources, materials, food, tools
• Adventure — quest items, keys, artifacts
• Simulation — resource management and item tracking

Demo: A fully working demo scene with sample items, styled slots, and a functional hotbar

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Demo Assets Notice: The item graphics, icons, and UI visual samples included in this package are strictly for demonstration purposes. These artwork assets are NOT granted for commercial use or redistribution. You must replace all demo icons and graphics with your own custom assets before publishing your game.